Indicator of detonations for internal combustion engines



Dec. 27, 1938. M. Y. A. sE1QRuYs 2,141,416

INDICATOR 0F DETONA'IIONS FOR INTERNAL COMBUSTION ENGINES Filed Dec. 17,1934 T Patented Dec. 21,1938

mmcs'ron or DETONATIONS FOR IN- TERNAL conmus'rron ENGINES Max YvesAntonin S erruys, Paris, France Application December 17, 1934, SerialNo. 757,873

, In France December 21, 1933 '1 Claim. Apparatus for measuring thevalue of the impact due to the detonating action of internal. combustionengines are in use at the present.

time, and in particular the apparatus termed 5 'Bouncing'pin, which ismounted by the'General Motors Company upon certain engines used fortesting. Such apparatus are characterized by the use of a small chamberor thin flat metallic diaphragm subjected to the pressure, a

10 vibrating rod in contact with the said diaphragm, an electriccontact-device actuated by the said rod, and an electric apparatus formeasuring the mean current passing through the said contact device.

Other detonation responsive devices are known, which include a diaphragmresponsive to engine pressure. contact meansin'cluding a contact carriedby the diaphragm and a second contact, and I indicating means responsiveto separation or to mutual engagement of said contacts.

All the aforesaid apparatus are responsive to the pressure whichprevails in the explosion chamber of the cylinder under test.

The primary object" of my invention is to pro- -vide a detonationresponsive device which will be irresponsive to the pressure in theexplosion chamber.

With this aim in view, I make use as a detonation responsivedevice of adevice responsive to pressure-acceleration including a diaphragmresponsive to engine pressure and contact means including a contactcarried by the diaphragm, and in which resilient means normally hold asecond contact in engagement with the first named contact, the forceexerted by the resilient means and the mass of the second contact beingsuch that under normal operation the second contact-will follow andremain in contact with the first, but under a detonation the secondcon-- 40 tact will separate from the first, and indicating meansresponsive to the opening of the contacts. The accompanying drawingshows by way of example an. embodiment of the invention.

As shown in the drawing, the detonation indicator, which is secured tothe cylinder head I and is connected with the explosion chamber 2,comprises a small block 3 secured to a diaphragm I, which is mounted. bya non-leaking joint, in

the main body I of the indicator, and whose.

5 lower side 3 is connected, by a conduit with the explosion chamber 2.As shown in the drawing, the conduit I has practically the form ofaventuri, thus aflordlng the most approved transmission of theinstantaneous pressure' to the dia- 55 'phragm 4. A movable block 3 isplaced indirect contact, in the idle position, with the block 3 by aspring 3. The block Sis guided by aninsulatins disc l0, and thediaphragm 4, the disc- Ill and a packing ring H are held in position bya go plug II. The block 3 is electrically connected through the spring 9and a metallic rod l3, insulated at It, with an induction coil l5, whoseprimary is supplied by a source of current ll whose other end isconnected to earth by the metal parts, as well as the cylinder head I.The

secondary l8 of the coil is connected with a neon tube' IS. Thediaphragm, the blocks 3 and 8,

and the spring 9 are so designed that during the normal working of theengine, the spring 9 will constantly hold the block 8 against the block3 but when the explosion in the chamber 2 has the-character of adetonation; the block 3 will be imparted an acceleration greater thanthat imparted to the block 8 by the spring 9, so that "the block 3 willseparate from the block 8 .dur-

ing the return stroke of the diaphragm to its rest position, thusbreaking the primary circuit l6 and producing an induced high-tensioncurrent in the secondary l8, hence lighting the neon tube l9.

It is important to note the following: 1. The block 8 is in directcontact with the block 3, without the interposition of any vibratingrod, which aifords a very small and light device.

2. The spring 9 can be easily adjusted in such way that thenon-detonating explosions can never separate the contact blocks 3 and 8,but that any slight detonations will break this contact.

3. The neon tube may be permanently mounted on the front board or on thecontrol board of an aeroplane or automobile, or testing bench containingthe engine under test, or upon a moving part of said engine, and theposition of this part, at the time when the tube lights up, will showthe point of the cycle at which the detona-.- tion takes place; such anarrangement of the invention can be madeby any person skilled in theart, and need not be further described.

4. The apparatus "can be used notonly as an .apparatus for observationor control, but as a safety device, and especially upon an aeroplane, inorder to attract the attention of the pilot each time that an impropermaneuver or a defective operating of the engine causes it to detonate.

What. I claim is:

In a detonation responsive device for internal combustion engines meansincluding a diaphragm responsive to engine pressure and contact meansincluding a contact carried by the diaphragm, a second contact,resilient means for normally holding the latter in, engagement with thefirst-named contact, the force exerted by the resilient means and themass of the second-contact being such that under normal operation thesecond contact will follow and remain in contact with the first, butunder a detonation the second contact will separate from the first, andindicating means responsive to the opening of the contacts.

MAX YVES ANTONIN SERRU'YS.

